CARSON, Calif. -- Typed into the official play-by-play, the most critical moment for the Denver Broncos' defense on Sunday will not look all that imposing: "P. Rivers short middle to A. Ekeler to DEN 1 for no gain (K.Jackson)."

But safety Kareem Jackson's stop of Los Angeles Chargers running back Austin Ekeler as time expired in the first half is worth underlining for a defense desperately in need of superlative plays.

"Huge, huge," Broncos coach Vic Fangio said. " ... Those are the types of plays we had envisioned when we brought Kareem in here to play safety."

The Broncos earned their first victory of the season, 20-13, thanks to the points Jackson saved before halftime. His hit just before the goal line forced Ekeler to fumble through the end zone for a touchback.

Despite Denver leading 17-0 after scoring on three of its first four possessions, the Chargers were having a moment of sorts in those final minutes of the first half.

The Chargers had taken over on their own 25-yard line with 5 minutes, 17 seconds left and had effectively moved the ball to the Broncos' 10-yard line with 20 seconds to go. After an incompletion on first down, quarterback Philip Rivers hit Mike Williams for a 7-yard pass on second down.

"And we were still thinking right there, we have to make some plays," linebacker Alexander Johnson said. "Just keep them out, that's what we were thinking."

On third down, Johnson stopped Ekeler short of the goal line so the Chargers faced a fourth-and-goal from the 1. Chargers coach Anthony Lynn elected to go for the touchdown.

"That was my decision," Lynn said. "Trying to create some momentum in this football team, trying to get us a score before the half and come back out and get the ball again and get another score. I gambled and lost."

Jackson said the Broncos talked about the potential of Ekeler on "some jet sweep action," and that's exactly what the Chargers did. Cornerback Isaac Yiadom made Ekeler take a wider angle and Jackson used that little bit of space to roar into Ekeler just before the goal line, knocking the ball free for a touchback.

"[Yiadom] made him bow his course, gave Kareem time to get there," Fangio said.

"Great call by Coach Fangio, I was able to make a play," Jackson said. "... Throughout the course of any game, there's going to be a couple plays that decide the game, and I think it was a huge play for the team. ... We've been preaching the last few weeks, find a way to make one or two plays as a team."

It was a huge play for a Broncos' defense that waited four games to have its first sacks of the season and waited until Sunday's fifth game before it got its first turnover on defense. The Broncos had interceptions by safety Justin Simmons and Johnson to go with a fumble recovery.

The hope now is that the defense has shaken loose from at least some of the troubles of the season's first month, when their hard work wasn't always rewarded.

"I'm really just happy for this team, these guys," Fangio said. "I know the results don't show it and results can obscure a lot of things, justifiably so, but these guys have been doing everything we ask for them. They fought."